An ancient river landscape dating back millions of years in Antarctica has been detected by scientists as being buried under more than a mile of ice.
This discovery gives us a glimpse of a long-lost Antarctic world, shaped by rivers and plants.
The new study is also key to helping scientists predict how the continent might respond to human-caused climate change in the future.
Antarctica is almost entirely covered by ice sheets, but millions of years ago the continent was inhabited by dinosaurs and other animals, when it was part of a much warmer part of the supercontinent Gondwana .
Even after the supercontinent broke up, Antarctica continued to support lush vegetation and tundra ecosystems, until becoming largely glaciated over the past 20 million years.
The frozen landscapes of Antarctica iStockphoto by Getty Images
The scientists, led by Stewart Jamieson, a glaciologist at Durham University, used satellite observations to peer beneath two kilometers (1.25 miles) of a region called the East Antarctic Ice Sheet (EAIS).
The team managed to detect “a vast relict preglacial landscape preserved beneath the central EAIS despite millions of years of ice cover”, suggesting that there are “other similar ancient landscapes, as yet undiscovered , under the EAIS”.
During a call with VICEJamieson said: “We have long been interested in the shape of the land beneath the Antarctic ice sheet, and in particular how the shape of this landscape interacts with the ice itself to control it, but also in terms of recording his behavior in the past, so that he leaves a signature, or a fingerprint.
“What we’re trying to do is identify places where we can really see an obvious picture of the land under the ice and map it,” he continued. “
The East Antarctic ice sheet has existed for 34 million years. It’s a piece of ice that lasts a very long time and we want to use the landscape to try to understand if we can actually see anything about the stability of the ice sheet. »
Jamieson and his colleagues had to figure out how to look through this extremely thick and ancient patch of ice. The team therefore turned to data collected by the Canadian satellite constellation RADARSAT. This makes it possible to detect tiny anomalies on the ice surface that hint at the topography below.
Jamieson used this technique to fill in some of the missing gaps in survey observations made over the past several decades. The results revealed the remains of a bygone landscape the size of Wales, which researchers estimate is more than 34 million years old.
“The implication is that this must be a very ancient landscape that was carved by rivers before the ice sheet itself developed,” Jamieson explained.
“This is why we can say that the landscape itself is probably more than 34 million years old. It was a time when the climate was a little warmer. There was vegetation and plants in Antarctica, but there was no large-scale ice. »
Jamieson and his colleagues hope to extract more details on the ground using remote sensing methods so they can reconstruct how the ice sheet changed over time. Because the EAIS is “known to be sensitive to past and potentially future global and ocean warming,” this information could help scientists understand how this immense sheet might respond to human-caused climate change.
The study is published in Natural communications.
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